Abstract : If it has been show in previous studies (as [5, 2]) that most IR models satisfy most IR constraints, the situation of the TDC constraint is unclear, and the goal of this short paper is to show that several state-of-the-art IR models indeed do not comply with the general TDC constraint, but do satisfy the speTDC one. We will review here the recently intro- duced log-logistic model [2], as well as the Jelinek-Mercer and Dirichlet language models.